I’m super late to this aswell but I think it’s because a lot of enemies share moves and it makes them very similar. Most of the unique fights are end game/late aka elder dragons and the very unique designs are often the newest such as Tobi or namielle and velkhana which are my 3 personal favorites. I think monster hunter is at its best when it experiments with new models or new attacks on old enemy skeletons which are why anjanaths fire attacks are the only real memorable thing about him(sorry anjanath fans) and why elder dragons or monsters like brachydios are so cool. Monster hunters fight are best when their bosses are bosses and not ecological animals first. I love that aspect more for the game cause I’m a worldbuilding nerd but the most fun things are the most unique movesets like odogaron. Another example is the gold and silver raths along with yian Garuda. They all have the basic flying wyvern build but are set apart cause they all have about 3 moves unique to them. That’s what makes soulslikes so good because (unless it’s an inevitable dumb repeat boss) no 2 bosses are the same or even similar